Scatter Plots & Trend Lines

Fitting a line to data

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Scatter plots show relationships between two variables.
• The least-squares line minimises the total squared residuals.
• Interpolation is fairly safe; extrapolation and outliers can mislead.

Steps

1. Two variables at once
2. Fit the line
3. Make a prediction
4. Extrapolation
5. A perfect line
6. Same numbers, different pictures
7. One outlier